Due to the serious and debilitating nature of arteriosclerosis and its prevalence among the United States population many devices have recently been proposed and clinically tested that in some way relieve the detrimental effects of stenotic and occlusive lesions in the vascular system.
The "Transluminal Lysing Device" more specifically relates to surgical instruments capable of excising and removing from the body the biological material that makes up stenotic or occlusive lesions of biological lumens and are also operable from a location outside of the lumen or location outside of the body.
The following are prior art inventions having one or more similar characteristics or physical appearance attributes, or a similar resultant action to the invention described herein.
U.S. Pat. No. 4,030,503 Clark "Embolectomy Catheter" shows an open coil of round or half round wire and a central core wire used for support, but shows no method for enclosing material for removal from the body. Although its appearance is similar to the Transluminal Lysing Device, it does not perform the excision and removal process described by the invention herein.
U.S. Pat. No. 3,683,891 Eskridge et al., "Tissue Auger" shows an open coil of sharply disposed flat wire but shows no means for retaining tissue for removal other than friction along the smooth inner walls of the retainment chamber.
U.S. Pat. No. 4,653,496 Bundy et al., "Transluminal Lysing System" shows a flexible variably spaced coil of specially shaped and sharpened wire and a co-acting cutting cannula. Although some of the elements of the Transluminal Lysing Device are similar to those elements found in the "Transluminal Lysing System" the co-action of the elements work together in a very different manner to cause a different resultant action (i.e. the cutting mode) to achieve the same objectives of arterial patency and flow improvement.
Several U.S. Patents, (i.e. Banko, Kerfoot, Royce, et al.) show devices that remove tissue with an auger or auger and slot type arrangement. The baffle plate in the distal end of the Transluminal Lysing Device might be considered to operate in the fashion of an auger during engagement of the lesion material The auger type devices as a whole are inflexible and might not negotiate the tortuous blood vessels that need to be traversed to excise atherosclerotic and other lesions. The cutting action of most of these devices is that of a high speed rotary chipper or mill that creates small particles for removal through the auger. The creation of a large number of small particles in a blood vessel increases the chances for one of these particles to escape into the distal flow to cause embolic phenomenon, and is contrary to the objectives of this invention.
Technical and clinical information concerning a device called the Simpson Shaver was disseminated at the Texas Heart Institute Annual Interventional Cardiology Meeting in 1986 in Houston, Texas. The device has an inflexible tip that acts as a receiver for a rotating bolt or blade that has a sharp edge. Material is cut from the vessel wall and stored inside the end of the receiver. This tool is more selective than the Transluminal Lysing Device shown here. The selectivity is due to limitations of its construction in that it cannot remove material located directly in front of its distal end and is therefore incapable of removing total obstructions. Also due to the small portion of the tool's total volume that is used for material storage, several trips must be made to unload the storage compartment.
Although the above mentioned prior art shows one or more similar attributes in appearance or action to the Transluminal Lysing Device described herein. No prior art shows the unique cutting action or operational method, or material enclosure technique as shown in this invention.
The primary advantages of the present invention with respect to the prior art are brought about by its unique construction and method of operation The open coils of the Transluminal Lysing Device allow fast engagement with little torsional resistance since all cutting does not take place during rotation This also allows for deeper penetration. The lesion material which is still firmly attached to the lumen wall during engagement is more efficiently loaded relatively into the retainment chamber for subsequent excision and removal than in the prior art. Since the forces required for operating the tool are applied from outside the lumen, a large amount of energy can be expended and larger cutting forces applied during the excision process than is possible with similar prior art. The method described herein allows the excision process to be divided into discrete incremental parts engagement and excision. Energy for the former applied by torsional forces in the transport structure and energy for the latter applied by tensile and compressive forces in the core guide wire and support structure respectively. Another useful advantage is the high volumetric efficiency of this device. Through compression and containment during excision, the tool can clear a volume of material almost as large as its own closed volume. The device also clears a volume proportional to its length in one operation or trip (an operation involving the insertion and/or removal of a tool from a hole or shaft).
Other advantages of the invention will be apparent in the following specifications.
______________________________________ FIELD OF SEARCH United States Classifications: 604/22, 46,47,49,52,53,164 264,266,267,274,281; 128/305,305F,310,751,753,754,755. References: ______________________________________ 2,850,007 "Biopsy Device" Lingley 3,082,805 "Tissue Macerator" Royce 3,683,891 "Tissue Auger" Eskridge 3,732,858 "Apparatus for removing Banko blood clots . . . " 3,749,085 "Vascular Tissue Removing Willson Device" 3,945,375 "Rotatable Surgical Instrument" Banko 3,976,077 "Eye Surgery Device" Kerfoot 4,030,503 "Embolectomy Catheter" Clark 4,177,797 "Rotary Biopsy Device Baylis and Method . . . " 4,512,344 "Arthroscopic Surgery Barber Dissecting Apparatus" 4,653,496 "Transluminal Lysing System" Bundy ______________________________________